It must be accurate to show exactly, where the dog is and super fast…that’s why 2.5 seconds, also you set the parametr on your hendhold and it will alert you if he crosses it instantly. Also he can get Halo colar for 500$ what he can set the imaginary fence and it will also show him when the dog crosses. It will beep, than vibrate and than very mild shocks for 100 feet, but you can’t call him yourself like with the garmin. Your idea is half as good if you stay on the top of it, I am sure that if you get lucky ones to catch him and shock him he is not going to try for another three weeks, so you can get the cheep shocking collar and put it on his dog until he learns if he agrees to it.